While new buildings have been constructed in accordance with stringent fire prevention and safety standards, it is an all too frequent occurrence that people are killed because of entrapment in upper floors of buildings by fire. Although portable safety line reel type fire escape devices have been proposed heretofore to my knowledge none of these has seen any significant degree of actual use.
A major problem encountered in producing a safety line reel type fire escape is the need to show the descent of the human body carried by the free end of the support line to a reasonable preferably constant rate of descent. Thus, in the prior art various mechanical braking devices were utilized to show rotation of the reel during unwinding of the line as in U.S. Pat. No. 383,432.
Also the prior art considered, in U.S. Pat. Nos. 1,145,923 and 3,861,496, the use of a piston coupled to the spool for forcing a fluid or granular material through a restricted orifice. Unfortunately, these techniques did not result in a substantially constant descent rate and were inherently expensive and bulky.